Calling for help: emergency call, whistle and mirror, ground signs compared

How do I get rescuers' attention?

Phone emergency call, signal whistle and signal mirror, and ground-to-air signs compared. The methods complement rather than replace each other. Range and visibility figures are deliberately not given – they depend heavily on terrain, weather and wind.

Starting situation

Legend
Method	Without mobile signal	Without a battery	Reaches help beyond hearing and sight	Conveys details	Works without constant action	Little physical effort
Making an emergency call: what to say, staying reachable	Depends	No	Yes	Yes	No	Yes
Signal whistle and signal mirror: basics	Yes	Yes	No	No	No	Depends
Ground-to-air signs	Yes	Yes	Partly	Partly	Yes	No

Legend:● Yes◐ Partly◇ Depends○ No* = note available

Making an emergency call: what to say, staying reachable

Effort:: Low
Needs:: Phone with battery and connection, knowledge of the local emergency number (112 in the EU)

Without mobile signalDepends
Needs a connection. Whether other networks or satellite features step in depends on device and country – not assessed here.
Without a batteryNo
Needs a charged battery; save battery after the call.
Reaches help beyond hearing and sightYes
Reaches the dispatch centre regardless of distance, as long as there is a connection.
Conveys detailsYes
Location, what happened, number of people, injuries – and the dispatcher can ask questions and give guidance.
Works without constant actionNo
Works only through the call; stay reachable afterwards.
Little physical effortYes
A short, structured call.

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Signal whistle and signal mirror: basics

Effort:: Low to moderate
Needs:: Whistle within easy reach, signal mirror and sunshine

Without mobile signalYes
No technology, no network needed.
Without a batteryYes
Battery-free.
Reaches help beyond hearing and sightNo
Only works if someone is within hearing or sight; wind, terrain and rushing water reduce the range.
Conveys detailsNo
Only signals ‘someone here needs help’, no details.
Works without constant actionNo
Only works while you actively blow or flash.
Little physical effortDepends
A whistle saves voice and energy; a mirror needs sun and practice.

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Ground-to-air signs

Effort:: High
Needs:: Open area, high-contrast material (stones, branches, clothing, tarp)

Without mobile signalYes
No technology needed.
Without a batteryYes
Battery-free.
Reaches help beyond hearing and sightPartly
Only for aircraft flying over the area; barely visible in forest and under cloud.
Conveys detailsPartly
Only simple messages such as ‘SOS’.
Works without constant actionYes
Works continuously, even while you rest or sleep.
Little physical effortNo
Laborious to build – pace your energy.

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